Browsing by Author "de Menezes, A.S."

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    Bi-phasic BiPO4 prepared through template-assisted hydrothermal method with enhanced electrochemical response for hybrid supercapacitor applications
    (Springer Science and Business Media B.V., 2023-03-27T00:00:00) Monteles, Iara A.; Penha, Bruno V.; Fonseca, Weliton S.; Silva, Let�cia M. B.; Santos, Evelyn C. S.; de Souza, Luiz K. C.; Santos, C.C.; de Menezes, A.S.; Sharma, Surender K.; Javed, Yasir; Khawar, Muhammad R.; Tanaka, Auro A.; Almeida, Marcio A. P.
    Abstract: We report the structural evolution of BiPO4 prepared in aqueous under different synthesis conditions viz., templates and temperatures to explore their electrochemical performance for supercapacitor applications. The templates [(hexadecyltrimethylammonium bromide (CTAB)), sodium dodecyl sulfate (SDS)] were added in bismuth precursor solution at 60��C, alternatively ethylene glycol (EG), a less toxic additive was incorporated at 90��C. BiPO4 exhibits a monoclinic phase, whereas a hexagonal structure was observed with the addition of the templates SDS and CTAB. Interestingly, both monoclinic and hexagonal phases were obtained by the addition of EG. The presence of mixed phase was thoroughly validated through Raman spectra, where vibrational modes for both monoclinic and hexagonal phases of BiPO4-EG were witnessed. The effect of template was clearly seen through electron microscopy with a rod-like morphology with (no template) and unfaceted (template). The electrochemical behavior of the synthesized materials was investigated, and it was found that the mixed structure of BiPO4-EG exhibited the highest specific capacity (167.15 C�g?1) at a scan rate of 5�mV�s?1, good capacitance retention at high current densities of up to 10 A�g?1 and the lowest electrochemical series resistance (ESR) of 57 ?. Graphical abstract: [Figure not available: see fulltext.]. � 2023, The Author(s), under exclusive licence to Springer Nature B.V.
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    Enhanced photocatalytic activity of BiOBr/ZnWO4 heterojunction: A combined experimental and DFT-based theoretical approach
    (Elsevier B.V., 2023-03-28T00:00:00) Andrade, Alana O.C.; Lacerda, Lu�s Henrique da Silveira; Lage J�nior, M.M.; Sharma, Surender K.; Maia da Costa, M.E.H.; Alves, Odivaldo C.; Santos, Evelyn C.S.; dos Santos, C.C.; de Menezes, A.S.; San-Miguel, Miguel Angel; Filho, Francisco Moura; Longo, Elson; Almeida, Marcio A.P.
    We report a successful fabrication of BiOBr/ZnWO4 heterojunction with enhanced photocatalytic performance for degrading Rhodamine B dye validated by joint experimental and theoretical approaches. The structural and microstructural analysis indicate that the heterostructures consist of a mixed tetragonal/monoclinic phase with enhanced surface area, which is crucial for photocatalysis. The results indicate increased photocatalytic activity for heterojunctions since BiOBr/ZnWO4 heterostructure showed a better degradation rate for Rhodamine B dye as compared to BiOBr due to higher surface area, pore size, and better photogenerated electron-hole pair separation efficiency. Additional analyses using isopropanol, benzoquinone, and sodium azide scavengers analysis were performed, showing that superoxide radicals (O2?) as the main responsible for the photocatalytic degradation of investigated materials. The theoretical analysis offers a complete overview of the composition and electronic structure of the interface. � 2023 Elsevier B.V.